I suggest you look at the CQRS pattern. A good Java implementation is http://www.axonframework.org/. The advantage is the CQRS pattern that it is fairly simple, but highly scalable. So you can start small and simple with the confidence that you can tweak and optimise in the future to scale as required. There are good tutorials and support too. My team is using it for an industrial application and we have found that it has been very robust. It might take a bit of work to get your head around the concepts, but it is worthwhile in the end.

That helps, but in severe conditions, as we are having now, it is still no guarantee. The problem of http://en.wikipedia.org/wiki/Ember_attack after people are evacuated means that even building that are hundreds of meters from the fire can still burn down. The strategy in NSW is to evacuate if there is any risk to life, so we have the situation where many buildings have been lost but so far no lives.

The guys at http://www.virtualrealitytrainingsystem.com/ have created an interactive 3D simulation to evacuate entire coal mines (and other things). As far as I know, this is the only full 3D 360 degree simulation in the world and it is designed so that a group of 10 or 20 miners can work through detailed simulations with a trainer in their full equipment. I have seen a lot of virtual reality systems, and this is by far the most realistic one that I have seen. The users report that it is more like a coal mine than the concrete mock ups that they also use for training. Disclaimer - I did some work on it!